Scalar interfaces in digital images of turbulent flows

R. R. Prasad, K. R. Sreenivasan

Research output: Contribution to journalArticlepeer-review


A scalar interface is defined as the surface separating the scalar-marked regions of a turbulent flow from the rest. The problem of determining the two-dimensional intersections of scalar interfaces is examined, taking as a specific example digital images of an axisymmetric jet visualized by laser-induced fluorescence. The usefulness of gradient and Laplacian techniques for this purpose is assessed, and it is shown that setting a proper threshold on the pixel intensity works well if the signal/noise ratio is high. Two methods of determining the proper threshold are presented, and the results are discussed. As one application of the technique, the fractal dimension of the scalar interface is calculated.

Original languageEnglish (US)
Pages (from-to)259-264
Number of pages6
JournalExperiments in Fluids
Issue number4
StatePublished - Feb 1989

ASJC Scopus subject areas

  • Computational Mechanics
  • Mechanics of Materials
  • General Physics and Astronomy
  • Fluid Flow and Transfer Processes


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